<?php
/**
 *  Patches a file by applying a 'diff' file to it
 *
 *  Requires "patch" to be on the execution path.
 *
 *  Based on Apache Ant PatchTask:
 *
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
 
require_once 'phing/Task.php';

/**
 * Patches a file by applying a 'diff' file to it
 *
 * Requires "patch" to be on the execution path.
 *
 * @package phing.tasks.ext
 */
class PatchTask extends Task
{
	/**
	 * Base command to be executed (must end with a space character!)
	 * @var string
	 */
	const CMD = 'patch --batch --silent ';

	/**
	 * File to be patched
	 * @var string
	 */
	private $originalFile;

	/**
	 * Patch file
	 *
	 * @var string
	 */
	private $patchFile;

	/**
	 * Value for a "-p" option
	 * @var int
	 */
	private $strip;

	/**
	 * Command line arguments for patch binary
	 * @var array
	 */
	private $cmdArgs = array();

	/**
	 * Halt on error return value from patch invocation.
	 * @var bool
	 */
	private $haltOnFailure = false;

	/**
	 * The file containing the diff output
	 *
	 * Required.
	 *
	 * @param string $file  File containing the diff output
	 * @return void
	 * @throws BuildException if $file not exists
	 */
	public function setPatchFile($file)
	{
		if (!is_file($file))
		{
			throw new BuildException(sprintf('Patchfile %s doesn\'t exist', $file));
		}
		$this->patchFile = $file;
	}

	/**
	 * The file to patch
	 *
	 * Optional if it can be inferred from the diff file.
	 *
	 * @param string $file  File to patch
	 * @return void
	 */
	public function setOriginalFile($file)
	{
		$this->originalFile = $file;
	}

	/**
	 * The name of a file to send the output to, instead of patching
	 * the file(s) in place
	 *
	 * Optional.
	 *
	 * @param string $file   File to send the output to
	 * @return void
	 */
	public function setDestFile($file)
	{
		if ($file !== null)
		{
			$this->cmdArgs []= "--output=$file";
		}
	}

	/**
	 * Flag to create backups
	 *
	 * Optional, default - false
	 *
	 * @param bool $backups  If true create backups
	 * @return void
	 */
	public function setBackups($backups)
	{
		if ($backups)
		{
			$this->cmdArgs []= '--backup';
		}
	}

	/**
	 * Flag to ignore whitespace differences;
	 *
	 * Default - false
	 *
	 * @param bool $ignore  If true ignore whitespace differences
	 * @return void
	 */
	public function setIgnoreWhiteSpace($ignore)
	{
		if ($ignore)
		{
			$this->cmdArgs []= '--ignore-whitespace';
		}
	}

	/**
	 * Strip the smallest prefix containing <i>num</i> leading slashes
	 * from filenames.
	 *
	 * patch's <i>--strip</i> option.
	 *
	 * @param int $num number of lines to strip
	 * @return void
	 * @throws BuildException if num is < 0, or other errors
	 */
	public function setStrip($num)
	{
		if ($num < 0)
		{
			throw new BuildException('strip has to be >= 0');
		}

		$this->strip = $num;
	}

	/**
	 * Work silently unless an error occurs
	 *
	 * Optional, default - false
	 * @param bool $flag  If true suppress set the -s option on the patch command
	 * @return void
	 */
	public function setQuiet($flag)
	{
		if ($flag)
		{
			$this->cmdArgs []= '--silent';
		}
	}

	/**
	 * Assume patch was created with old and new files swapped
	 *
	 * Optional, default - false
	 *
	 * @param bool $flag  If true set the -R option on the patch command
	 * @return void
	 */
	public function setReverse($flag)
	{
		if ($flag)
		{
			$this->cmdArgs []= '--reverse';
		}
	}

	/**
	 * The directory to run the patch command in
	 *
	 * Defaults to the project's base directory.
	 *
	 * @param string $directory  Directory to run the patch command in
	 * @return void
	 */
	public function setDir($directory)
	{
		$this->cmdArgs []= "--directory=$directory";
	}

	/**
	 * Ignore patches that seem to be reversed or already applied
	 *
	 * @param bool $flag  If true set the -N (--forward) option
	 * @return void
	 */
	public function setForward($flag)
	{
		if ($flag)
		{
			$this->cmdArgs []= "--forward";
		}
	}

	/**
	 * Set the maximum fuzz factor
	 *
	 * Defaults to 0
	 *
	 * @param string $value  Value of a fuzz factor
	 * @return void
	 */
	public function setFuzz($value)
	{
		$this->cmdArgs []= "--fuzz=$value";
	}

	/**
	 * If true, stop the build process if the patch command
	 * exits with an error status.
	 *
	 * The default is "false"
	 *
	 * @param bool $value  "true" if it should halt, otherwise "false"
	 * @return void
	 */
	public function setHaltOnFailure($value)
	{
		$this->haltOnFailure = $value;
	}

	/**
	 * Main task method
	 *
	 * @return void
	 * @throws BuildException when it all goes a bit pear shaped
	 */
	public function main()
	{
		if ($this->patchFile == null)
		{
			throw new BuildException('patchfile argument is required');
		}

		// Define patch file
		$this->cmdArgs []= '-i ' . $this->patchFile;
		// Define strip factor
		if ($this->strip != null)
		{
			$this->cmdArgs []= '--strip=' . $this->strip;
		}
		// Define original file if specified
		if ($this->originalFile != null)
		{
			$this->cmdArgs []= $this->originalFile;
		}

		$cmd = self::CMD . implode(' ', $this->cmdArgs);

		$this->log('Applying patch: ' . $this->patchFile);

		exec($cmd, $output, $exitCode);

		foreach ($output as $line)
		{
			$this->log($line, Project::MSG_VERBOSE);
		}

		if ($exitCode != 0 && $this->haltOnFailure)
		{
			throw new BuildException( "Task exited with code $exitCode" );
		}

	}
}